Congress under the ARTICLES OF CONFEDERATION was a unicameral body representing thirteen states. But delegates to the CONSTITUTIONAL CONVENTION, influenced by the example of the British Parliament and almost all of the states, agreed rather early to the principle of a two-house legislature. Members of the HOUSE OF REPRESENTATIVES were to be popularly elected, with each state's members proportionate to population. But membership in the SENATE and selection of senators caused intense controversy.
The large states wanted the Senate also to represent population, but the smaller states were adamantly opposed. They forced a compromise under which every state would have two senators, elected by the state legislatures for six-year terms. This solution gave effect to the federal principle, the Senate representing the states and the House providing popular representation. However, legislative election of senators ultimately proved unacceptable. During the nineteenth century the elections were often marked by scandals and deadlocks, and a rising progressive temper in the country led to adoption of the SEVENTEENTH AMENDMENT in 1913 providing for direct popular election of senators.
The size of the House was initially set by Article I at sixty-five, to be revised thereafter on the basis of decennial censuses. As the population grew and more states were admitted to the Union, Congress increased the number of seats until it reached 435 after the 1910 census. Congress then concluded that further enlargement would make the House unwieldy, and by statute in 1929 fixed 435 as the permanent size of the House.
After each census the 435 House seats are apportioned among the states according to a statutory formula. It is then the responsibility of each state legislature to draw the lines for congressional districts. There was initially no legal obligation to assure equality of population among districts. Particularly in the early twentieth century rural-dominated state legislatures refused to revise district lines to provide equitable representation for growing urban areas. Judicial relief failed when the Supreme Court in COLEGROVE V. GREEN (1946) ruled that drawing the boundary lines of congressional districts was a POLITICAL QUESTION for decision by the state legislatures and Congress, not the courts. This HOLDING was implicitly overruled by the Court in BAKER V. CARR (1962), and in WESBERRY V. SANDERS (1964) the Court made equality...